The present invention is directed to improvements to cylinder locks.
Cylinder locks consist of a stator or housing which is also known as a block, having a barrel for a rotor or cylinder (also known as plug) that rotates within the barrel. The lock is provided with tumblers which are pin-like elements that sit within a part of a radial bore hole that extends from the keyway in the rotor, crossing the rotor into the stator. The tumbler is positioned proximally to the keyway. The bore extends into the stator, and there is a second pin like element within the stator, that is biased towards the tumbler by a biasing spring that is held in place by a plug that blocks the distal end of the bore.
The perimeter of the cylinder, where it contacts the barrel is known as the shear line. To rotate the cylinder, none of the tumblers or driver pins may bridge the shear line. The features of the correct key within the keyway position the tumblers and drivers in the correct positions so that none bridge the shear line, enabling the key to be rotated, rotating the cylinder with it.
Rotating the cylinder with respect to the stator unlocks the lock and typically allows the retraction of one or more latches or bolts, allowing a door to be opened. This can only happen if all the tumbler pins are within the rotor and all the driver pins are within the stator such that no part of any pin bridges the divide between the stator and the cylinder. This is achieved by the proximal element or pin lying fully within the cylinder and the distal element or pin lying fully within the bore in the stator.
The cylinder is provided with a key way into which a corresponding key may be inserted. The corresponding key has protrusions or indentations that toggle the tumblers and align their ends with the shear line, i.e. the perimeter between the stator and cylinder to allow the cylinder to be rotated.
In general, the more tumblers that are provided, the better the lock and the more difficult it is to force since the number of key options increases exponentially with the number of tumblers.
The key may have a jagged edge, as common in Yale® locks, a cylindrical shank as common in Chub® locks, or a flat key with indentions as is common in Rav Bareach® locks.
Rav Bareach® have a well deserved reputation for their quality locks. The Rav Bareach® lock is a cylinder lock that is opened using a flat blade dimpled key. Each dimple engages and toggles a different tumbler. The depth and position of the dimples provides different key-lock combinations. In high security locks, the shape of the depressions may also vary.
Mul-T-lock has developed the so-called 3 in 1 system wherein a lock is provided with three color coded keys, typically red, yellow and green. The green key is the basic one for opening the lock as provided. Insertion and turning of a yellow coded key causes the end of one or more pins to break and changes the configuration of the lock so that the red key will no longer open it, with the yellow key becoming the key for the lock. This provides a convenient way to change the configuration of a lock twice, without having to remove and change the lock cylinder.
There are various improvements and variations to this type of lock-key combination. For example, USSN 2012/0055212 to Nicoara provides a further layer of sophistication to Rav Bariach's lock and key combinations, by providing flat blade keys mutually compressible actuating elements, that are essentially telescopic studs that align with and compress the pins of a tumbler and which make duplicating the key more difficult. The pins used are compound pins that include an inner pin and an outer pin housing. Both pin and outer pin housing have beveled edges that enable them to slide up and down as the key is inserted into the keyway.
There is an ongoing need to provide additional security features, and there is value in enabling locks to be reconfigured using a key, without having to change cylinders.
The tumblers that are pushed up into the bores of the stator by the key are sometimes known as pins. This term is appropriate if the element is a simple cylinder. In some locks, more sophisticated elements are provided. For example, in German Utility Design DE 202004015051 titled “Locking cylinder for door lock comprises a housing pin having a first pin part and a second pin part which slide into each other and a spring acting between the first and second pin parts for moving the pin parts”, an element consisting of male and female components around a spring is shown—see FIG. 3 thereof. Insertion of the key causes the male component to be squeezed into the female component, compressing the spring. On removal of the key, the spring causes the male component to move with respect to the female component, restoring the overall length.
European patent number EP0763639 titled “Pin tumbler and lock cylinder with such a pin tumbler” also show a compressible element (referred to as a bolt) with an internal spring. The compressible element has a male component or shaft with a protruding ring referred to as a shaped outer ridge around the shaft, that can be moved in and out of a cylindrical housing or female component referred to therein as a mounting bore, with the protruding ring configured to slide within a circumferential indention referred to therein as a widened section, that keeps the male part (shaft) locked within the female part (mounting bore), but allowed the overall element to be compressed by applying a force that overcomes the resilience of the spring. On releasing the compressive force, the spring expands, forcing the male element (shaft) to slide outwards to assume its outer configuration, the protrusion being stopped by the end of the circumferential indentation. Sometimes these compressible elements are referred to as pins, but this is somewhat confusing.
https://www.reporteditor.com/reports/report/bc8b718491be21b8/publication1 titled “Key Operated Locks” describes a method of changing the effective lengths of the tumblers of a Yale™ type lock, using a special reconfiguring keys. The effective lengths of the tumblers may be shortened or lengthened.
U.S. Pat. No. 3,589,153 titled “Key Operated Lock” describes a key operated lock including a housing having a cylindrical bore therethrough in which a plug is rotatably mounted. Apertures extend radially outwardly in the housing from the bore and each slideably receives a driver. Each driver is aligned, in one position of the lock, with a tumbler assembly movably positioned in an aperture in the plug. The tumbler assembly—receiving apertures communicate with a main key slot in the plug, and insertion of a main key in this slot biases the several tumbler assemblies to a lock opening position in which the tumbler assemblies contact the drivers along a shear line lying in the interface between the plug and body. The tumbler assemblies are adjustable in their dimensions so that they may be altered to permit a new key to be made operative for opening the lock. Each tumbler assembly includes two relatively moveable parts which are interlocked by a locking pin until it is desired to alter the assembly's dimension for key changing purposes. The locking pins are cammed to the interlocking positions by cam plates. These cam plates line up with the driver apertures when the plug is rotated to a key changing position, and in this position, a change key can be inserted in a change key slot in the plug to bias each locking pin to a position in which the two relatively movable parts of each tumbler assembly are disengaged. The tumbler assemblies can then automatically accommodate their dimensions to an entirely different main key inserted in the main key slot. Thus a second key is required in a second key slot to reconfigure the main key.
U.S. Pat. No. 8,347,678 titled “Rekeyable Lock Cylinder Assembly” describes a rekeyable lock cylinder assembly includes at least one lock cylinder and a mortise lock adapter. Each lock cylinder includes a cylinder body with a longitudinal axis. A locking bar is disposed in the cylinder body for movement transverse to, and rotationally about, the longitudinal axis. A plug assembly having a tool receiving aperture is disposed in the cylinder body and is rotatable about the longitudinal axis. A plurality of pins and a corresponding plurality of racks are disposed in the plug assembly. A first member is moveable in response to application of a force by a tool received through the aperture to simultaneously disengage all of the plurality of racks from the plurality of pins. The mortise lock adapter includes a housing configured for receiving the cylinder body of the lock cylinder. A mortise lock actuator is coupled to the plug assembly of the lock cylinder.
U.S. Pat. No. 7,634,931 titled “Rekeyable Lock Cylinder Assembly With Adjustable Pin Lengths” describes a rekeyable lock cylinder includes a plug body and a backing rack that cooperate to define a plurality of pin chambers within the lock cylinder, with each of the pin chambers housing a corresponding pin. Movement of the backing rack changes the configuration of the pin chambers, thereby allowing the corresponding pins to change configuration to match the bitting on a valid key.
U.S. Pat. No. 4,732,023 titled “Modifiable Cylinder” describes a modifiable cylinder which comprises a plug and a cylinder body. The plug fits into the cylinder body and has a keyway and a plurality of bottom pin holes which are disposed above and perpendicular to the keyway. Each of the bottom pin holes has a bottom pin. The cylinder body comprises a main chamber housing and a subchamber housing. The main chamber housing has a plurality of top pin holes, each of which has a spring and a top pin. In open position, the top in hoes are aligned with the bottom pin holes. The subchamber housing has a plurality of top pin holes, each of which has a spring, a top pin and several discs. When the plug is turned to the modifying position, the top pin holes are aligned with the bottom pin holes so that the discs can be moved into the bottom pin holes so as to modify the inner combination of the cylinder.
European Patent Number EP 2,184,426 titled “Lock Cylinder, In Particular for a Door Lock” describes a lock wherein the closing cylinder has a housing containing a first spring acting on a housing pin and a core rotating in a cavity. A second spring is fitted between the first pin part and the second pin part. This spring is stressed in the direction of the core. The first pin part is in the form of a shell, and the second one has a widened end facing the core.
U.S. Pat. No. 3,802,234 titled “Pick-Resistant Lock Construction Including Jamming Feature” describes a keyed, pin tumbler type lock that has one or a series of jamming pin members in the casing intermediate the path of rotation of the lock cylinder between locked and unlocked positions. Attempted rotation of the lock cylinder from locked toward unlocked position without use of the key permits the jamming pin members to move inwardly partially into the lock cylinder jamming it against further rotation to the unlocked position. The jamming pin members are axially split pins outwardly axially abutted by spring urged wedge members which force the split pins partially into the lock cylinder pin openings while radially separating the split pins to engage them axially outward with casing shoulders, thereby permanently positioning the jamming pins in lock cylinder jamming position.